dwe8922

I have a DAS rollbar, with the harness guides set for a one piece seat. Even with the shoulder straps "correctly" spaced, my harnesses still work their way off on occasion. I called HANS the other day, and they recomended I try crossing the shoulder strap mounting position (creating an X between the rollbar and back of the seat). I won't get to test this until August, but I thought I'd pass it along since this topic of slippage has come up before, and many of you use the HANS. He told me that this was based on new data. Also, I originally asked about the "surfaced" tape that people were saying came on the new devices to help the belts stay put. Yes, their is a new surface, but he said that the devices have always had a rubber portion on the shoulder strap (I didn't believe him until I looked at mine--its a very hard rubber), and that the performance difference between the different iterations is negligible.

Dbltime

The non skid tape on the old style HANS has way less grip than the new style surface material. I bought a roll of boat deck non skid tape. Have not tried it out yet. I will try crossing the harnesses as well. My wife thinks my shoulders are too skinny and rounded. Are you a small frame guy David?

ltc

IIRC from previous discussions, crossing the harnesses is done if the harness length behind the collar/seatback exceeds 16"

Here is a recent thread discussing this and belt crossing (see second page of link below):
https://rennlist.com/forums/racing-and-drivers-education-forum/198648-my-hans-devise-attacked-me-again-and-dunlops.html

and here is a Schroth document for reference (thank you rennlist use m758):
http://members.rennlist.com/m758/06_...lder_Belts.pdf
(one of the photos shows a 50mm distance between belts for HANS use)

Here is a link to an FIA document on HANS:
http://www.fia.com/resources/documen...HANS_Guide.pdf
Page 5 shows a crossed harness installation.

FWIW, I have always been concerned about the evolving use/design/recommendations behind the HANS and harnesses.

As an engineer, all the recent threads tend to reinforce my initial assessment (re: gut check or first impression) of the HANS design; the tendancy for belts to slip off the device is inherent in the design (re: wings, no wings, back to wings, various friction materials, various belt designs/geometries, recommendations for sternum straps, HANS specific seats, etc).

Human phyisology (i.e. the angle of the shoulders/collarbone relative to the neck/HANS) drives the initial positioning/alignment issues which drives belt slippage...IMHO. The photographs in the Schroth document listed above show the initial angles of the belts being DOWN and tilted AWAY from the person's shoulders/neck. Again, it's simply driven by human anatomy; after that, the physics and Newton's laws of motion are in play.

It is not an endorsement for a different device, nor a slam against the HANS.
The simple realities of design is that there IS no perfect design. Every design involves compromises/tradeoffs and revisions/iterations.

As has been stated in the past, just about ANY H&N restraint is better than no H&N restraint. The cold reality is that you and your device will be tested only once (in a severe impact); it is at that point where you and the design will be validated.

RedlineMan

Hey;

For cars with belt bars more than 18-20" behind the seat, Schroth is recommending that the belts indeed be crossed. In the 12" range, you really should have them mounted pretty close together. This creates an "inward tension" on the tightened belt that helps keep it nearer the neck, and therefore on the HANS.

Also, the height of the belt bar is somewhat critical. It should be no more than an inch or two below the tops of your shoulders. Any more than that causes compression on the collar at the shoulders, which in turn tends to leverage the frontal "tips" of the collar away from your chest. This tends to want to flip the belts off the HANS.

Along with these items, you really need seat holes that are not only close together, but at the proper height. Holes below your shoulders simply won't do in any event, but especially with a HANS. Shorter folks have an advantage here.

I do not have too much trouble with my belts staying on. Cranking the shoulder down really tight helps a lot, and I check that the belts are staying inward over my chest once or twice a lap, which I can do rather subconsciously. The new Schroth 2"/3" shoulder system is said to work much better. I also have a HANS modification I am toying with that will help greatly.

dwe8922

I'm 6'3", so I don't feel like my shoulder width is a problem. I would also agree that the newer more textured tape would help. Let us know how the non skid tape works out.

My height puts my seat within 12" from the bar I'm pretty sure. Also, since I hardmounted the seat to maximize headroom, the shoulder straps are pretty much parallel (if the seat were higher, the angle of the belts would be greater. For me, slippage seems to be less of a problem than for others (from what I've read), but still enough to be a concern. I don't get much track time right now with school, so my sampling is pretty small, but I've started just cranking the belts down as tight as I can stand, which seems to help quite a bit. I'm going to try crossing the belts for August. My only concern was that with a 3" belt, it will be at a greater angle (right to left) at the mount, causing more pressure on the outside than inside portion of the belt. HANS told me that would not be an issue.

Another thing is that a 3" belt is a tad wider than the guide portion of the HANS that is directly over the shoulder. So, when the belts are tightened, part of the belt is already off the HANS. I wonder if that accentuates the slippage?

Bill Gregory

Schroth makes several Hans-specific harnesses with a 2" shoulder belt width.

mitch236

I wonder if anyone has any thoughts about putting metal straps accross the shoulder portions of the HANS with the harness belts under the straps. Sort of like the way the HANS keeps their straps secured at the back of the device. Of course that would mean the HANS is now mounted to your harness and would make getting in and out much more cumbersome, but it would solve the slipping off problem.

Eric in Chicago

While racing with NASA this weekend (Putman Park) there was a rep from HANS Midwest walking the paddock this weekned checking out HANS users set ups and giving out info. I had her look at my set up to make sure everything was the way it should be and she gave me some interesting info.
The new design (little lips on the edges) were desigined to overcome improper mounting of the shoulder belts. Kind of a fail safe for people that dont mount the belts per instruction or cant for whatever reason (wide seat shoulder holes, roll bar mounting/height issues). She also told me that only a inch of belt needs to be on the harness at impact, thats it, a inch, not the whole belt webbing covering the harness. She also mentioned that the harness I am using (Team Tech) with sterum strap was not advised. The harness has extra built in padding that is not the same texture as the belts, the grip on the HANS is not as good as the belts .She also warned about the sterum strap being connected. It a crash, the belts ride up and if the sterum strap is attached, bad things are going to happen around you neck... Just thought I would share some first hand info right from the HANS's mouth

ceboyd

hmmm.... I was having all sorts of problems with my HANS as well... ....and worked with HANS directly and then the midwest rep too when they were at RA.... in my case, I actually had to get different seats to make my hans work properly for me...

...so I had to say bye-bye to my comfy pole positions....

NOW I have only a driver side seat... no more passenger for a while (mounting the new seat was a PITA and only the driver side is mounted at the moment).. BUT at least my HANS will work properly now..

...see, in my case... my shoulders were way above the harness openings on the pole positions.. which caused an extreme amount of pressure ONLY on my shoulders and not spread evenly thoughout the hans... which caused severe downforce on my shoulders making it extremely difficult to concentrate on the track with all the downforce pressure on my shoulders..


It is amazing how evenly the force is distributed with the harness seat holes even with my shoulders and not 2" below... go figure...

Clem

ceboyd - can I ask what type of seat you moved to? I also have this problem with my pole positions. I remove the bottom cushion, but my shoulders are still 3" above the passthroughs. The problem has really been compounded by the use of the HANS.

CarreraCup03

I use the HANS with a Pole Position and 5 pt Schroth harness and do not get any slippage of the belts. I am carefull that they are lined up when I tighten the belts and make the belts very tight. The harness holes are above my sholders.

ceboyd

yes.. it is called UltraShield Pro Race

their website is www.ultrashieldrace.com


I sold my Pole Positions to a VW owner so I kept my recaro seat brackets and sliders.. they are now holding in the ultrashield seat (but it required custom new spacers and you have to drill your own mounting holes in the seat)

NOTHING else I sat in worked for my height as far as the composite seats I could actually sit in... and I wasn't about to spend $1500+ on the one Recaro composite seat designed to accomodate the HANS.. notice how only one Recaro seat has HANS on it?


I should have said that the 2" was with the hans cushion removed.. been there.. tried that...


Here is what I ended up with:




...since my car is red, I opted for that exact red stripe... and the nice thing about that seat is it is set up for my 6 point belts (so it doesn't just have 1 opening on the bottom of the seat but 3)... --- 1 for a 5-poing sub hole... and 2 more specificly for a 6 point... I really like it..

Although I will admit it is not as soft and comfortable on my butt as the pole position... yet is isn't uncomfortable either.... the next day at the track will tell me for sure...

ceboyd

that is why it works for you... because the harness holes are above your shoulders!!!!

Clem

Thanks for the info. This seat looks like it could work. I like the idea of the Recaro Hans specific seat (with the taller passthroughs) but the halo won't quite work since I drive the car on the street.

ltc

How does this (aluminum) seat fit into the 2005 PCA Club Racing rules regarding seat back braces:
http://www.pca.org/pca/clubrace/docs/pca_rules_2005.pdf
Section 25 (page 8 of 24):
25. All cars will be equipped with a seat back brace except as provided in Safety Rule 26 below. Said
device will mount securely to the roll cage/bar and will rest firmly against the back of the seat. The
portion that contacts the seat will be a minimum of twelve (12) square inches and larger is suggested.
The seat construction must be compatible with the seat back brace and not pose a hazard to the
driver. The seat back brace for composite seats must have a minimum of thirty (30) square inches
contacting the seat back, and must have 0.5” to 2” of high density foam padding between the brace
and the seat back. The seat back brace cannot be bolted to a composite seat.
It sounds as though a seat of this construction (i.e. not composite) will require the seat back braces to be bolted to the seat?

IIRC, Redlineman (John H) has been an advocate of these seats for a while now and I"m sure he knows the answer.